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HANDBOOK OF PHYSIOLOGY. 



tiona, or ends as they are called, of the stomach, are partially separated 

 from each other by a kind of hour-glass contraction. By means of the 

 peristaltic action of the muscular coats of the stomach, not merely is 

 chymified food gradually propelled through the pylorus, but a kind of 

 double current is continually kept up among the contents of the stomach, 

 the circumferential parts of the mass being gradually moved onward 

 toward the pylorus by the contraction of the muscular fibres, while the 

 central portions are propelled in the opposite direction, namely toward 

 the cardiac orifice; in this way is kept up a constant circulation of the 

 contents of the viscus, highly conducive to their free mixture with the 

 gastric fluid and to their ready digestion. 



Influence of the Nervous System. The normal movements of 

 the stomach during gastric digestion do not appear to be so closely con- 



R.V 



0.6 



D.7 



D.8 

 0.9 



Fig. 253. Very diagrammatic representation of the nerves of the alimentary canal. Oe to Ret, 

 the various parts of the alimentary canal from oesophagus to rectum; L. V, left vagus, ending on 

 front of stomach; rl, recurrent laryngeal nerve, supplying upper part of oesophagus; R.V, right 



intestine, and from the mesenteric ganglia to the large intestine; Spl.maj.. large splanchnic nerve, 

 arising from the thoracic ganglia and rami communicantes; r.c. belonging to dorsal nerves from 

 the 6th to the 9th (or 10th) ; Spl.min., small splanchnic nerve similarly from the 10th and llth dorsal 

 nerves. These both join the solar plexus, and thence make their way to the alimentary canal; c.r., 

 nerves from the ganglia, etc., belonging to llth and 12th dorsal and 1st and 2d lumbar nerves, 

 proceeding to the inferior mesenteric ganglia (or plexus), m.gl., and thence by the hypogastric 



nerve, n.hyp., and the hypogastric nerve, n.hyp., and the hypogastric plexus, pl.hyp., to the circular 

 muscles of the rectum ; l.r.. nerves from the 2d and 3d sacral nerves. S.2, S.3 (nervi erigentx 

 proceeding by the hypogastric plexus to the longitudinal muscles of the rectum. (M. Foster.) 



tes) 



nected with the plexuses of nerves and ganglia contained in its walls as 

 was formerly supposed. The action, however, appears to be set up by 

 the presence of food within it. The stomach is, moreover, directly con- 

 nected with the higher nerve-centres by means of branches of tr vagi 

 and of the splanchnic nerves through the solar plexus. 



